With the rapid development of information technology, the use of multimedia technology in a network has undergone an unprecedented development. Video communications technology, as an important part of the multimedia technology, has also developed vigorously and has been widely used. Since different videos may adopt different encoding or compression standards and specific application scenarios may also be different, an operation of video transcoding is often desirable when video files are shared, exchanged or played among different devices.
Video Transcoding refers to converting a compressed and encoded video bit stream into another video bit stream to adapt for a different bandwidth, a different terminal processing capability, and a different user requirement. In essence, transcoding is a process of decoding and then encoding, and such process may involve conversion between different video formats, for example, converting from MPEG-2 or MPEG-4 to H.264, and may further involve adjustments of transcoding parameters such as, a bit rate, a resolution and a frame rate, etc., so that a video that is generated after the transcoding operation can satisfy particular requirements. Examples include a reduction in a bit rate of encoding to adapt to a transmission scenario with a limited network bandwidth or a requirement on a playing speed of a terminal device, or an adjustment of an encoding resolution to convert a high definition video into a video with a standard definition or even a lower definition to reduce a space of storage media that is occupied by an associated video file.
Currently, a number of video enterprises have offered video transcoding tools. These video transcoding tools generally adopt traditional video transcoding technology, i.e., using preset video transcoding parameters (a resolution, a bit rate or a frame rate) for transcoding. Examples include using a fixed bit rate corresponding to a resolution of a video to be transcoded to perform a transcoding, or fixing a width of a video image, setting a height based on as aspect ratio, adjusting a bit rate according to a number of pixels and performing the transcoding.
As can be seen, the traditional video transcoding technology does not consider the complexity of video content to be transcoded and basically sets parameter values for video transcoding based on subjective experience, or merely considers one or more parameters of the video to be transcoded. As a result, the traditional video transcoding technology often cannot achieve effective transcoding of video files with different contents. For example, a waste of network bandwidth may result because of a higher bit rate used for encoding for a video having relatively simple content; and a deterioration in an overall definition of a video with complicated content may result after transcoding due to the use of a lower resolution for the video.